What is Kirlian photography?

Kirlian photograph of two coins exosphere.

Kirlian photography is a collection of photographic techniques used to capture the phenomenon of electrical coronal discharges. It is named after Semyon Kirlian, who, in 1939 accidentally discovered that if an object on a photographic plate is connected to a high-voltage source, an image is produced on the photographic plate.[1] The technique has been variously known as "electrography",[2]"electrophotography",[3] "corona discharge photography" (CDP),[4] "bioelectrography",[2] "gas discharge visualization (GDV)",[5] "eletrophotonic imaging (EPI)",[6] and, in Russian literature, "Kirlianography".